Ischemic peripheral vascular disease particularly of the lower extremity occurs in a significant portion of the population, with estimations that 100,000 or more amputations are performed annually for this problem. Inadequate blood flow to the skin of the leg is not only the primary cause for the amputations, but also for non-healing of the site following amputation. No acceptable clinical method currently exists to evaluate the level and adequacy of cutaneous flow in ischemic limbs. In this study we propose to evaluate the skin blood flow particularly at the microcirculatory level in the affected extremity using post-occlusive hyperemia and local heating as stress tests in combination with a laser Doppler instrument to monitor the induced changes in skin blood flow and to map microcirculatory flow patterns and gradients. This will be compared with results obtained from measuring transcutaneous oxygen levels (tcPO2) which is also being investigated as a measure of cutaneous perfusion. The hypothesis to be tested is that skin blood flow in severely ischemic limbs will not show significant increases in response to either transient arterial occlusion or local heating as compared to normal limbs, and that these stress tests represent a more critical test of cutaneous flow reserve and therefore healing capacity than does resting skin blood flow. It is also designed to test the difference in response between diabetics and non-diabetics with ischemic vascular disease.